The stereoselective reduction of the 6-keto group of certain morphinan compounds is a necessary step in the preparation of many opiate-based compounds. For example, 6-beta-hydroxy morphinan derivatives have valuable medical potential for the unmet needs of pain management and addiction therapy. Traditionally, a 6-beta-hydroxy epimer has been prepared by reducing the corresponding 6-keto compound in a large volume of an alkaline solution of formamidine sulfinic acid. Not only are the yields of the reaction low, but the reaction also generates large volumes of caustic waste material. If the reaction is run in a more concentrated environment, however, one of the components precipitates out of solution and the reaction stalls prior to completion. As a consequence, the resulting 6-hydroxy morphinan product is contaminated with large amounts of the unconverted starting material. Accordingly, a need exists for an efficient and scalable process for converting 6-keto-morphinans to 6-beta-hydroxy morphinans in pharmaceutical grade quality. The process should ensure high yield, high epimeric purity, and simple isolation of the desired compound.